If you are trying to transfer a domain but it has failed due to there being no email verification, this is likely because you cannot access the current administrative contact email address or you have taken too long to verify it (you have up to 5 days to respond). An email is sent to this address during a domain transfer which contains a link that must be clicked to verify that the transfer is genuine.
Search the WHOIS record
Search a global WHOIS database to find out who the administrative contact email address is for your domain - WHOIS Domain Tools.
Updating the Administrative Contact
If your domain name has been registered by us, you can update the administrative contact information by following the instructions in this help article - 'How do i change my whois contact information?.'
If your domain has not been registered by us, you would need to contact the registrar where this was done. Most commonly there would be an admin login for you that you can access in order to update the records.
Initiating Domain Transfer again
To initiate the domain transfer again, you may need to obtain a new EPP key if the previous one has expired. Go to the new registrar to start the domain transfer process again. Now that the administrative email account is accessible, the transfer can be verified and proceed to the next phase.